The invention pertains to the art of motion transmitting mechanisms, machine elements, and linkages.
1. Field of the Invention
More particularly a linkage is required for operating a control valve of an hydraulic system. For a vehicle such as a skid-steered tractor vehicle having boom arms which can be raised and lowered and an attachment carrier pivoted on the front of the boom arms, this involves a control valve for hydraulic cylinders both to raise and lower the boom arms and for pivoting the attachment carrier on which is usually mounted a bucket, backoe or the like.
2. Description of the Prior Art
A skid-steered tractor vehicle of the type referred to is disclosed in U.S. Pat. No. 3,866,700 issued Feb. 18, 1975 to the inventor; James J. Bauer, and is assigned to the assignee of the present invention. A variety of linkage rods, machined parts and threaded connectors are used for assembling the various components of the linkage and to provide adjustment. For convenience reference is made to the aforementioned patent and particularly FIG. 20, Columns 12, 13 and 14; lines 53-68; 1-68 and 1-12, respectively, describing the control valve and hydraulic system for such a vehicle.
Linkages for controlling the boom arms and attachment carrier of such a vehicle have, heretofore, used threaded parts which are relatively expensive. Repairs are time consuming. Also visual inspection does not detect a malfunction or out of adjustment condition.